JP3433678B2 - Antimony-doped silicon single crystal wafer and epitaxial silicon wafer, and methods for producing them - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epitaxial silicon single crystal wafer for producing a semiconductor device having a small amount of heavy metal impurities harmful to the reliability of the device existing in an epitaxial layer, and an antimony-doped silicon single crystal wafer used as a substrate thereof, and It relates to these manufacturing methods.

[0002]

2. Description of the Related Art Epitaxial silicon single crystal wafers are widely used for individual semiconductors and bipolar I because of their excellent characteristics.
It has been used for a long time as a wafer for producing C and the like. Further, MOS LSIs are also widely used in microprocessor units and flash memory devices because of their excellent soft error and latch-up characteristics. Furthermore, the demand for epitaxial silicon single crystal wafers is ever expanding in order to reduce the reliability defects of DRAM due to so-called grown-in defects that are introduced during the production of silicon single crystals.

However, in recent research, even with such an epitaxial wafer, depending on the conditions of the epitaxial process and the epitaxial film thickness, the Grown-i existing on the surface of the substrate wafer after the epitaxial growth.
It has been pointed out that the influence of n-defects becomes apparent (Kimura et al., Journal of the Japan Society for Crystal Growth Vol.24 No.5 p.444, 1997).

In particular, an antimony-doped N-type substrate (hereinafter referred to as an antimony-doped silicon single crystal wafer) used for a low-resistance device has a larger atomic radius of antimony than silicon, and thus is a normal boron compound. Compared to a P-type substrate doped with Si (hereinafter, referred to as a boron-doped silicon single crystal wafer).
High density of n defects
This is a problem because the influence of n-in defects is much larger than that of other substrates.

If heavy metal impurities are present on the epitaxial silicon single crystal wafer used for such a semiconductor device, characteristic defects of the semiconductor device are caused. Especially, the cleanliness required for the most advanced devices has a heavy metal impurity concentration of 1 × 10 ¹⁰ atoms / cm ²
The heavy metal impurities present on the silicon wafer, which are considered to be below, should be reduced as much as possible.

The gettering technique is becoming more important as one of the techniques for reducing such heavy metal impurities. Conventionally, N-type substrates such as phosphorus-doped silicon single-crystal wafers and antimony-doped silicon single-crystal wafers have been used as substrate wafers for epitaxial growth in the manufacture of epitaxial silicon single-crystal wafers for CCD. However, these N-type substrates have a problem that oxygen precipitation is less likely to occur as compared with a boron-doped silicon single crystal wafer. The lack of gettering ability due to the lack of oxygen precipitation amount of the N-type substrate is a fatal problem in a device such as CCD that is sensitive to crystal defects caused by heavy metal impurities.

Particularly, in the case of an antimony-doped silicon single crystal wafer, when a silicon single crystal rod doped with antimony is grown by the Czochralski method, the oxygen concentration in the latter half of the growth of the single crystal rod having a high antimony concentration is antimony oxide. It is very difficult to maintain a high oxygen concentration due to the evaporation of. For this reason, the oxygen concentration is lowered, so that the oxygen precipitation of the silicon wafer cut from this portion is suppressed, and the gettering ability required for device manufacturing cannot be obtained.

Therefore, in order to obtain the same amount of oxygen precipitation as the boron-doped silicon single crystal wafer in the antimony-doped silicon single crystal wafer, a longer oxygen precipitation heat treatment is required than in the boron-doped silicon single crystal wafer. However, there was a problem that productivity was deteriorated.

If the oxygen concentration of the wafer can be increased in order to increase the oxygen precipitation amount of the antimony-doped silicon single crystal wafer, the oxygen precipitation is promoted and the time required for such heat treatment is shortened. However, the oxygen precipitation amount of the wafer becomes excessive, which causes problems such as deformation of the wafer and reduction of the strength of the wafer. Further, when an epitaxial layer is formed on the surface of this antimony-doped silicon single crystal wafer, there is a problem that harmful defects are generated in the epitaxial layer due to outward diffusion of impurity oxygen, which adversely affects the epitaxial layer. Further, if the oxygen content is high, so-called grown-in defects frequently occur, which leads to deterioration of the quality of the epitaxial layer.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is an antimony-doped silicon single crystal wafer having a grown surface on the wafer.
A silicon wafer for epitaxial growth which has high gettering ability even though oxygen concentration in the substrate is suppressed to such an extent that it does not cause problems such as deformation of the wafer and reduction in the strength of the wafer. , And an epitaxial silicon single crystal wafer having an epitaxial layer with a low defect and an extremely low concentration of heavy metal impurities, which is grown using the wafer as a substrate wafer, with a high productivity.

[0011]

[Means for Solving the Problems] To solve the above problems
The present invention is an antimony-doped silicon single crystal wafer, characterized in that the density of crystal defects on the surface of the antimony-doped silicon single crystal wafer is 0.1 unit / cm ² or less. Is.

As described above, the antimony-doped silicon single crystal wafer, in which the density of crystal defects on the surface of the antimony-doped silicon single crystal wafer is 0.1 ke / cm ² or less,
This is a silicon single crystal wafer in which the density of Grown-in defects on the surface of the wafer is suppressed to be extremely low as compared with the conventional antimony-doped silicon single crystal wafer.
Therefore, if such an antimony-doped silicon single crystal wafer is used as a substrate wafer for producing an epitaxial wafer, an epitaxial silicon single crystal wafer having a high-quality epitaxial layer can be obtained.

The present invention is also an antimony-doped silicon single crystal wafer, wherein the density of oxygen precipitates or oxidation-induced stacking faults after the precipitation heat treatment of the antimony-doped silicon single crystal wafer is 1 × 10 ⁹ pieces / cm ³ or more. Is an antimony-doped silicon single crystal wafer.

As described above, the antimony-doped silicon single crystal wafer has an oxygen precipitate or oxidation-induced stacking fault density of 1 × 10 ⁹ pieces / cm ³ or more after the precipitation heat treatment of the antimony-doped silicon single crystal wafer. Since the antimony-doped silicon single crystal wafer has a very high gettering ability, it becomes a silicon single crystal wafer having an extremely low density of heavy metal impurities on the surface of the wafer. Therefore, if such an antimony-doped silicon single crystal wafer is used as a substrate wafer for producing an epitaxial wafer, an epitaxial silicon single crystal wafer having a high-quality epitaxial layer can be obtained.

Furthermore, the present invention is an antimony-doped silicon single crystal wafer, wherein the density of crystal defects on the surface of the antimony-doped silicon single crystal wafer is 0.1 /
The antimony-doped silicon single crystal wafer is characterized in that the density is cm ² or less and the density of oxygen precipitates or oxidation-induced stacking faults after the heat treatment for precipitation is 1 × 10 ⁹ defects / cm ³ or more.

Thus, in the case of an antimony-doped silicon single crystal wafer, the density of crystal defects on the surface of the antimony-doped silicon single crystal wafer is 0.1 unit / cm ^2.
An antimony-doped silicon single crystal wafer having an oxygen precipitate after oxidation heat treatment or an oxidation-induced stacking fault density of 1 × 10 ⁹ pieces / cm ³ or more has a density of grown-in defects on the surface of the wafer is It is a silicon single crystal wafer which is extremely suppressed as compared with the antimony-doped silicon single crystal wafer described in (1) and has a very high gettering ability, so that the silicon single crystal wafer has an extremely low concentration of heavy metal impurities on the surface of the wafer.
Therefore, if such an antimony-doped silicon single crystal wafer is used as a substrate wafer for manufacturing an epitaxial wafer, an epitaxial silicon single crystal wafer having an extremely high quality epitaxial layer can be obtained.

The invention according to claim 4 of the present invention is
An antimony-doped silicon single crystal wafer, wherein the antimony-doped silicon single crystal wafer is characterized in that it is obtained by slicing a silicon single crystal rod grown by nitrogen doping by the Czochralski method. It is an antimony-doped silicon single crystal wafer.

As described above, the antimony-doped silicon single crystal wafer is obtained by slicing a silicon single crystal rod grown by nitrogen doping by the Czochralski method. If so, the density of Grown-in defects on the wafer surface is remarkably reduced due to the influence of nitrogen. Further, since oxygen precipitation is promoted by the presence of nitrogen in the bulk portion of the wafer, even if the oxygen concentration in the substrate is a relatively low concentration that does not cause problems such as deformation of the wafer and reduction in the strength of the wafer. The heat treatment for a short time has a high gettering effect.

Further, when such an antimony-doped silicon single crystal wafer is used as a substrate wafer for producing an epitaxial wafer, since the grown-in defects on the surface of the substrate wafer are small, the adverse effect on the epitaxial layer is extremely small. A short time heat treatment has a high gettering effect, and the concentration of heavy metal impurities in the epitaxial layer can be significantly reduced. Therefore, an epitaxial silicon single crystal wafer having an extremely high quality epitaxial layer can be obtained with high productivity.

In this case, it is preferable that the nitrogen concentration of the antimony-doped silicon single crystal wafer is 1 × 10 ^{10 to} 5 × 10 ¹⁵ atoms / cm ³ . This is because in order to suppress the formation of so-called grown-in defects in the antimony-doped silicon single crystal wafer by nitrogen and to promote oxygen precipitation sufficiently,
It is desirable to make it 1 × 10 ¹⁰ atoms / cm ³ or more,
In order not to hinder the crystallization of a silicon single crystal in the Czochralski method, 5 × 10 ¹⁵ atom
This is because it is preferably s / cm ³ or less.

Further, as described in claim 6, the oxygen concentration of the antimony-doped silicon single crystal wafer is
It can be 20 ppma (JEIDA: Japan Electronic Industry Development Association standard) or less. 20p like this
If the medium and low oxygen content is less than or equal to pma, there is no fear of deformation of the wafer and reduction of the wafer strength, and in addition, formation of crystal defects in the antimony-doped silicon single crystal wafer can be suppressed, and the surface of the wafer can be suppressed. The formation of oxygen precipitates in the layer can be prevented. Therefore, when the epitaxial layer is formed on the wafer surface, the crystallinity of the epitaxial layer is not adversely affected. On the other hand, since oxygen precipitation is promoted by the presence of nitrogen in the bulk part,
Even with such medium and low oxygen, the gettering effect can be sufficiently exerted.

Further, as described in claim 7, the antimony-doped silicon single crystal wafer is 900 ° C.
~ It is preferable that a heat treatment is performed at a temperature equal to or lower than the melting point of silicon. Thus, if the antimony-doped silicon single crystal wafer is heat-treated at a temperature of 900 ° C. to the melting point of silicon or lower, nitrogen and oxygen on the surface of the antimony-doped silicon single crystal wafer are diffused outward, The crystal defects in the surface layer of the antimony-doped silicon single crystal wafer are extremely small. Further, when a high temperature heat treatment such as formation of an epitaxial layer is performed thereafter, the precipitation nuclei do not melt and precipitation does not occur, and the wafer has a sufficient gettering effect.

The invention described in claim 8 is an epitaxial silicon single crystal wafer, and
An epitaxial silicon single crystal wafer having an epitaxial layer formed on a surface layer portion of the antimony-doped silicon single crystal wafer according to any one of claims 1 to 7.

Thus, the epitaxial silicon single crystal wafer in which the epitaxial layer is formed on the surface layer portion of the antimony-doped silicon single crystal wafer according to any one of claims 1 to 7 of the present invention is a substrate. Although the grown-in defects on the surface of the wafer have very little influence on the epitaxial layer and the oxygen concentration in the substrate is suppressed to such an extent that problems such as wafer deformation and wafer strength reduction are not caused, copper or copper Since a heavy metal such as nickel has a high gettering effect in a short time heat treatment and the concentration of heavy metal impurities is extremely reduced, a highly productive epitaxial silicon single crystal wafer having a high quality epitaxial layer is obtained.

According to a ninth aspect of the present invention, in the method of manufacturing an antimony-doped silicon single crystal wafer, a silicon single crystal rod doped with antimony and nitrogen is grown by the Czochralski method, The method for producing an antimony-doped silicon single crystal wafer is characterized in that the silicon single crystal ingot is sliced and processed into a silicon single crystal wafer.

As described above, in the method for producing an antimony-doped silicon single crystal wafer, a silicon single crystal rod doped with antimony and nitrogen is grown by the Czochralski method, and the silicon single crystal rod is sliced to obtain silicon. When an antimony-doped silicon single crystal wafer is manufactured by processing it into a single crystal wafer, the density of Grown-in defects on the surface of the wafer is remarkably reduced due to the influence of nitrogen. Further, since oxygen precipitation is promoted by the presence of nitrogen in the bulk portion of the wafer, even if the oxygen concentration in the substrate is a relatively low concentration that does not cause problems such as deformation of the wafer and reduction in the strength of the wafer. The antimony-doped silicon single crystal wafer having a high gettering effect can be manufactured by the heat treatment for a short time.

Further, when the antimony-doped silicon single crystal wafer manufactured by such a method is used as a substrate wafer for manufacturing an epitaxial wafer, a grown-in defect on the surface of the substrate wafer has a bad influence on the epitaxial layer. To obtain an epitaxial silicon single crystal wafer with an extremely high quality epitaxial layer with high productivity, as it has a high gettering effect with a small number of short-time heat treatments and can significantly reduce the concentration of heavy metal impurities in the epitaxial layer. You can

In this case, as described in claim 10,
When growing a silicon single crystal ingot doped with nitrogen by the Czochralski method, the concentration of nitrogen doped in the single crystal ingot is preferably set to 1 × 10 ^{10 to} 5 × 10 ¹⁵ atoms / cm ^3, and As described in claim 11, the oxygen concentration contained in the single crystal rod can be set to 20 ppma or less, and further, as described in claim 12, the antimony-doped silicon single crystal wafer has 900 ° C. to silicon. It is preferable to apply heat treatment at a temperature equal to or lower than the melting point of

When the antimony-doped silicon single crystal wafer is manufactured in this manner, the antimony-doped silicon single crystal wafer having a higher gettering ability, less surface defects, and suitable for epitaxial growth with various characteristics is suitable. Can be manufactured.

According to a thirteenth aspect of the present invention, in the method for producing an epitaxial silicon single crystal wafer, the antimony-doped silicon single crystal wafer according to any one of the ninth to twelfth aspects is produced. A method for producing an epitaxial silicon single crystal wafer, which comprises producing an antimony-doped silicon single crystal wafer by a method and forming an epitaxial layer on a surface layer portion of the antimony-doped silicon single crystal wafer.

As described above, in the method for producing the epitaxial silicon single crystal wafer, the antimony-doped silicon single crystal wafer is produced by the above-described method for producing the antimony-doped silicon single crystal wafer, and the surface layer portion of the antimony-doped silicon single crystal wafer is produced. If the epitaxial layer is formed, the Grown-i on the surface of the substrate wafer is
Even if the n-defect has a very small effect on the epitaxial layer and the oxygen concentration in the substrate is suppressed to such an extent that problems such as wafer deformation and wafer strength reduction are not caused, a high-quality getter can be obtained by heat treatment for heavy metals in a short time. Due to the ring effect, the concentration of heavy metal impurities in the epitaxial layer can be significantly reduced, and an epitaxial silicon single crystal wafer having a high quality epitaxial layer can be manufactured with high productivity.

The present invention will be described in more detail below.
The present invention is not limited to these. The present invention is
A technique for doping an antimony-doped silicon single crystal wafer having a low grown-in defect density on the wafer surface and a high oxygen precipitate or oxidation-induced stacking fault density, particularly nitrogen during crystal growth. By using the obtained wafer as a substrate wafer for producing an epitaxial silicon single crystal wafer, the grown-in defects on the surface of the substrate wafer have very little effect on the epitaxial layer, and the gettering effect is high in a short time heat treatment. However, they have found that an epitaxial single crystal wafer having an extremely low concentration of heavy metal impurities can be manufactured with high productivity, and have scrutinized various conditions to complete the present invention.

That is, it has been pointed out that when nitrogen is doped into a silicon single crystal, aggregation of grown-in defects in silicon is suppressed and the density of grown-in defects in the single crystal is lowered (D. Graf, et al, Electroch
emical Society PreceedingSeries PV96-13,117,1996
). Furthermore, it has been pointed out that nitrogen in silicon single crystals promotes the agglomeration of interstitial oxygen atoms and increases the concentration of oxygen precipitates (T.Abe and H.Takeno, Mat.Res.Soc.Symp.Pro.
c. Vol. 262, 3, 1992). It is considered that these effects are caused by suppression of atomic vacancies by promoting pair annihilation of intrinsic point defects due to catalytic effect of impurity nitrogen, and heterogeneous nucleation of oxygen with impurity nitrogen as a nucleus.

Therefore, if nitrogen is doped when growing a silicon single crystal by the Czochralski method, Gr
A silicon single crystal with few down-in defects and a high oxygen precipitate concentration and a silicon single crystal wafer can be obtained by processing the silicon single crystal. By growing an epitaxial layer using this silicon single crystal wafer as a substrate, the adverse effect of the grown-in defects on the surface of the wafer on the epitaxial layer can be suppressed, and at the same time, the antimony-doped silicon single crystal wafer which is not likely to be precipitated with oxygen is expected. However, a high oxygen precipitate density can be obtained, and as a result, an epitaxial layer having an extremely low heavy metal impurity density can be grown. Further, since it is not necessary to increase the oxygen concentration in the wafer, problems such as wafer deformation and wafer strength reduction do not occur and the epitaxial layer is not adversely affected by impurity oxygen.

The antimony-doped silicon single crystal wafer manufactured by doping nitrogen during the growth of the silicon single crystal as described above is an antimony-doped silicon single crystal wafer which is originally said to be unlikely to precipitate oxygen and has a low gettering effect. Even if there is a high gettering effect, it is possible to form a high-quality epitaxial layer, and long-term gettering heat treatment is not required. It can also be expected to improve productivity and cost.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION In order to grow a silicon single crystal rod doped with antimony and nitrogen with the Czochralski method in the present invention, for example, as described in JP-A-60-251190. A known method may be used.

That is, according to the Czochralski method, a seed crystal is brought into contact with a melt of a polycrystalline silicon raw material contained in a quartz crucible, and this is slowly pulled up while rotating to grow a silicon single crystal rod having a desired diameter. It is a method to do, while putting the polycrystalline silicon raw material to which antimony was added in advance in the quartz crucible, put the nitride in the quartz crucible, or put the nitride in the silicon melt, By setting the atmosphere gas to be an atmosphere containing nitrogen or the like, nitrogen can be doped into the pulled crystal. At this time, the amount of nitrogen doped in the crystal can be controlled by adjusting the amount of nitride, the concentration of nitrogen gas, the introduction time, or the like.

As described above, when growing a single crystal ingot by the Czochralski method, by doping with nitrogen, the grown-in defects introduced can be reduced and the aggregation of oxygen atoms in silicon can be reduced. Can be promoted and the concentration of oxygen precipitates can be increased. This method does not need to slow down the pulling speed conventionally performed to reduce the grown-in defects,
Since the method can be easily performed by using the conventional manufacturing apparatus, it is possible to manufacture a silicon single crystal with high productivity without adding a new manufacturing apparatus or the like.

Further, conventionally, in the case of an antimony-doped silicon single crystal wafer, when a silicon single crystal rod doped with antimony is grown by the Czochralski method, the oxygen concentration in the latter half of the grown single crystal rod having a high antimony concentration is: It is very difficult to maintain a high oxygen concentration by evaporation of antimony oxide, and the extremely low oxygen concentration suppresses the oxygen precipitation of the silicon wafer cut from this site, which is necessary for device manufacturing. I couldn't get gettering ability. However, by doping nitrogen into the silicon single crystal as in the present invention, the gettering ability required for device manufacturing can be obtained without prolonging the heat treatment time or increasing the oxygen concentration.

When nitrogen is doped into a silicon single crystal,
Aggregation of Grown-in defects in silicon is suppressed,
As described above, the reason why the density of crystal defects on the wafer surface becomes smaller, the aggregation of oxygen atoms is promoted, and the concentration of oxygen precipitates becomes higher, is explained above. Is suppressed, and
It is considered that the aggregation process of oxygen atoms shifts from homogeneous nucleation to heterogeneous nucleation with impurity nitrogen as nuclei.

Therefore, the concentration of nitrogen to be doped is preferably 1 × 10 ¹⁰ atoms / cm ³ or more, which sufficiently promotes pair annihilation of true point defects and causes heterogeneous nucleation of oxygen.
This can suppress the generation of grown-in defects and can sufficiently increase the concentration of oxygen precipitates.
On the other hand, if the nitrogen concentration exceeds the solid solution limit of 5 × 10 ¹⁵ atoms / cm ³ in the silicon single crystal, single crystallization of the silicon single crystal may be hindered, so this concentration should not be exceeded. It is preferable to do so.

Further, in the present invention, since the concentration of oxygen precipitates is high even at low oxygen concentration, when growing a nitrogen-doped silicon single crystal ingot by the Czochralski method, the oxygen concentration contained in the single crystal ingot is controlled. It is possible to attain a medium or low oxygen concentration of 20 ppma or less. When the oxygen concentration in the silicon single crystal is 20 ppma or less, defects such as oxygen precipitates that deteriorate the crystallinity of the epitaxial layer can be prevented from being formed on the surface of the silicon single crystal wafer. It is possible to prevent the crystallinity of the epitaxial layer grown on the surface from being adversely affected. On the other hand, in the bulk portion, the precipitation of oxygen is promoted by the presence of nitrogen, so that the gettering effect can be sufficiently exhibited even with medium and low oxygen. It should be noted that the oxygen concentration is 18 pp in order to completely prevent the effect of promoting oxygen precipitation by nitrogen doping and the generation of harmful defects in the epitaxial layer due to outward diffusion of impurity oxygen.
It is preferably ma or less.

When growing a silicon single crystal ingot, a method for reducing the concentration of oxygen contained in the above range may be a conventionally used method. For example, the oxygen concentration range can be easily adjusted by means of reducing the number of rotations of the crucible, increasing the flow rate of introduced gas, lowering the atmospheric pressure, adjusting the temperature distribution and convection of the silicon melt.

In this way, a silicon single crystal ingot which is doped with antimony in the Czochralski method and with a desired concentration of nitrogen, has few crystal defects and contains a desired concentration of oxygen can be obtained. According to a usual method, after slicing with a cutting device such as an inner peripheral blade slicer or a wire saw, it is processed into a silicon single crystal wafer through steps such as chamfering, lapping, etching and polishing. Of course, these steps are only listed as examples, and there may be various steps such as cleaning and heat treatment in addition to these, and the steps are appropriately changed and used depending on the purpose such as changing the order of the steps or omitting some.

Next, before performing epitaxial growth, the obtained antimony-doped silicon single crystal wafer was subjected to 90%.
It is preferable to apply heat treatment at a temperature of 0 ° C. to the melting point of silicon or lower. By performing this heat treatment before forming the epitaxial layer, nitrogen on the surface of the silicon single crystal wafer can be diffused outward.

The outward diffusion of nitrogen on the surface of the silicon single crystal wafer is caused by the oxygen precipitation promoting effect of nitrogen, whereby oxygen is precipitated in the surface layer of the silicon single crystal wafer, and defects are formed based on this, which adversely affects the epitaxial layer. This is to prevent the occurrence of

In this case, since the diffusion rate of nitrogen in silicon is significantly higher than that of oxygen, the surface nitrogen can be surely diffused outward by applying heat treatment.
As a specific heat treatment condition, it is preferable to perform the heat treatment in a temperature range of 900 ° C. to the melting point of silicon, more preferably 1100 ° C. to 1200 ° C. By heat treatment in such a temperature range, nitrogen in the surface layer of the antimony-doped silicon single crystal wafer can be sufficiently diffused outward, and at the same time, oxygen can also be diffused outward. It is possible to almost completely prevent the occurrence of defects caused by the above and to prevent the crystallinity of the epitaxial layer from being adversely affected.

If the above-mentioned heat treatment is not performed before the epitaxial growth and the high temperature heat treatment for the direct epitaxial growth is applied, the oxygen precipitation nuclei are dissolved, and the precipitation is not sufficiently caused by the subsequent heat treatment. There is a concern that the ring effect cannot be obtained, but if the heat treatment as described above is performed before the high temperature heat treatment for epitaxial growth, a sufficient gettering effect can be obtained during the formation of the epitaxial layer and the heavy metal impurity concentration An extremely low epitaxial silicon single crystal wafer can be obtained. Furthermore, as a side effect, oxygen precipitates in the bulk of the wafer further grow and stacking faults (BS
In some cases, a stronger gettering effect may be exhibited by inducing F: Bulk Stacking Faults.

[0049]

EXAMPLES Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. (Example) By a CZ method, a quartz crucible having a diameter of 24 inches is charged with a raw material polycrystalline silicon to which a predetermined concentration of antimony is added, and a silicon wafer having a silicon nitride film is charged together with the raw material polycrystalline silicon. Then, the single crystal ingot having a diameter of 8 inches, N type, and orientation <100> was pulled at a normal pulling speed of 1.0 mm / min. When pulling the crystal, the crucible rotation was controlled so that the oxygen concentration in the single crystal was 20 ppma (J
EIDA) was set to be the following. In pulling the single crystal ingot, two single crystal ingots were pulled while changing the nitrogen doping amount.

The nitrogen concentration in the tails of these two single crystal rods was estimated by the calculated value by the segregation coefficient, and each was 1.0.
It was × 10 ¹⁴ atoms / cm ³ and 5.0 × 10 ¹⁴ atoms / cm ³ . Further, when the oxygen concentration of the single crystal rod was measured by the gas fusion method, both were 10 to 20 ppma.
It was confirmed that the oxygen concentration was.

From the two single crystal rods obtained here, a wafer was cut out using a wire saw, chamfered, lapped, etched and mirror-polished to obtain a silicon single crystal mirror-polished wafer having a diameter of 8 inches. 2 from a single crystal rod
A total of 4 sheets were prepared. When the resistivity of these four silicon single crystal wafers was measured, all four wafers had a resistivity of about 7-25.
mΩ · cm, which was within the range expected from the doping amount of the added antimony.

Before forming an epitaxial layer on the surface of each of these silicon single crystal wafers, heat treatment was performed at a temperature of 1100 ° C. to diffuse nitrogen on the surface of the wafer outward.
Further, in order to measure the crystal defect density on the wafer surface before epitaxial growth, these four silicon single crystal wafers were thoroughly washed, and then the crystal defect density on the wafer surface was measured using a particle counter.

Of the four silicon single crystal wafers cut out from these two silicon single crystal rods,
Of the two cut from the same single crystal rod, one is 120
At 0 ° C., the other one was grown at a temperature of 1125 ° C. to grow a 6 μm thick silicon epitaxial layer. The epitaxial growth furnace was of the leaf type, and the heating system was the lamp heating system. Silicon was epitaxially grown on the antimony-doped silicon single crystal wafer by introducing SiHCl ₃ + H ₂ into it.

In order to measure the gettering ability of the epitaxial wafers thus obtained, each wafer was heat-treated at 800 ° C. for 4 hours in an N ₂ gas atmosphere,
Heat treatment was performed at 1000 ° C. for 16 hours in an O ₂ gas atmosphere to deposit oxygen precipitates. After that, the gettering effect of these epitaxial silicon single crystal wafers was evaluated by the concentration of oxygen precipitates in the silicon wafer.

The measurement of the oxygen precipitate concentration is carried out by OPP (Opti
cal Precipitate Profiler) method. This OPP method is an application of a normalski type differential interference microscope, in which a laser beam emitted from a light source is first separated into two 90 ° linearly polarized beams having mutually different phases by a polarizing prism to obtain a wafer mirror surface. It is incident from the side. At this time 1
Phase shift occurs when one beam crosses the defect and the other
A phase difference between the two beams occurs. Defects are detected by detecting this phase difference with a polarization analyzer after passing through the back surface of the wafer.

On the other hand, in order to measure the effect of the crystal defects on the surface of the substrate wafer on the epitaxial layer, the crystal defect densities on the surface of these epitaxial silicon single crystal wafers after growth of the epitaxial layer were each 0.13 μm.
The particles having the above sizes were measured using a particle counter.

First, the measurement results of the crystal defect density before and after the epitaxial growth are shown in FIG. Here, the plot shown in the center of FIG. 1 shows a nitrogen doping amount of 1.0 × 10 ¹⁴ atoms / cm ³
The crystal defect density on the wafer surface is shown, and the plot on the right side shows the crystal defect density on the wafer surface with the nitrogen doping amount of 5.0 × 10 ¹⁴ atoms / cm ³ . And the circular plot shows the crystal defect density before epitaxial growth,
The triangular plot shows the crystal defect density after epitaxial growth. These numerical values show the average values of two wafers having the same nitrogen doping amount.

From FIG. 1, the nitrogen doping amount 1.0 × 10 ¹⁴ at
In both cases of oms / cm ³ and nitrogen doping amount of 5.0 × 10 ¹⁴ atoms / cm ³ , it can be seen that the crystal defect density on the wafer surface before and after the epitaxial growth is as low as 0.1 / cm ² or less. .

Next, the measurement results of the oxygen precipitate density after the oxygen precipitation heat treatment are shown in FIG. Here, the plot shown in the center of FIG. 2 shows the oxygen precipitate density of the wafer with a nitrogen doping amount of 1.0 × 10 ¹⁴ atoms / cm ³ , and the plot shown on the right side shows the nitrogen doping amount of 5.0 × 10 ¹⁴ atoms. The oxygen precipitate density of the wafer of / cm ³ is shown. The circular plot shows the oxygen precipitate defect density when the epitaxial growth was performed at 1200 ° C., and the triangular plot shows the oxygen precipitate defect density when the epitaxial growth was performed at 1125 ° C.

As shown in FIG. 2, the oxygen concentration of the wafer epitaxially grown on the surface of the nitrogen-doped antimony-doped silicon single crystal wafer is 10 to 20 ppma.
Despite being moderate, even if the epitaxial growth was performed at either temperature, a high oxygen precipitate density was similarly shown, indicating that a high gettering effect is obtained. Furthermore, the gettering heat treatment time required for manufacturing the epitaxial silicon single crystal wafer of this example requires only the same time as when using the boron-doped silicon single crystal wafer as the substrate wafer, which is Can be expected to improve.

(Comparative Example) 8 inch in diameter, N type, orientation <100, in the same manner as in Example except that nitrogen was not doped.
>, An antimony-doped silicon single crystal ingot having an oxygen concentration of 20 ppma or less was pulled up. Then, two silicon single crystal mirror-polished wafers having a diameter of 8 inches were produced from this single crystal rod in the same manner as in the example. The resistivity of the two silicon single crystal wafers is about 7 to 25 mΩ as in the case of the embodiment.
・ It was cm.

Then, the crystal defect densities on the surfaces of these silicon single crystal wafers were measured by a particle counter in the same manner as in the example except that the heat treatment for outdiffusion of nitrogen was not carried out. One at 1200 ° C and the other at a temperature of 1125 ° C with a thickness of 6
A μm silicon epitaxial growth was performed. Then, in the same manner as in Examples, oxygen precipitates are deposited on the obtained epitaxial wafers by heat treatment, and the gettering effect of these epitaxial silicon single crystal wafers is evaluated by the OPP method by the oxygen precipitate concentration in the bulk of the silicon wafers. At the same time, the crystal defect density on the wafer surface after the epitaxial growth was measured with a particle counter.

The measurement results of the crystal defect density before and after the epitaxial growth of the wafer of this comparative example are also shown in FIG. Here, the plot shown on the left side of FIG. 1 shows the crystal defect density on the surface of the wafer not doped with nitrogen. The circular plot shows the crystal defect density before the epitaxial growth, and the triangular plot shows the crystal defect density after the epitaxial growth. Each of these numerical values is an average value of two wafers.

From FIG. 1, the antimony-doped silicon single crystal wafer not doped with nitrogen has a crystal defect density of more than 0.5 / cm ² on the surface of the wafer before and after the epitaxial growth, and is doped with nitrogen. It can be seen that the crystal defect density is much higher than that of the wafer.

The measurement results of the oxygen precipitate density after the oxygen precipitation heat treatment of the wafer of the comparative example are also shown in FIG. Here, the plot shown on the left side of FIG. 2 shows the oxygen precipitate density of the wafer not doped with nitrogen. And
A circle plot shows the oxygen precipitate defect density when the epitaxial growth was performed at 1200 ° C., and a triangle plot shows the oxygen precipitate defect density when the epitaxial growth was performed at 1125 ° C.

From FIG. 2, it can be seen that the wafer epitaxially grown on the surface of the antimony-doped silicon single crystal wafer not doped with nitrogen has the same heat treatment time as when the boron-doped silicon single crystal wafer is used as the substrate wafer. Since the oxygen concentration is moderate at 20 ppma or less, it can be seen that the density of oxygen precipitates is low and the gettering effect is low regardless of which temperature the epitaxial growth is performed.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, has substantially the same configuration as the technical idea described in the scope of the claims of the present invention, and has any similar effect to the present invention. It is included in the technical scope of the invention.

For example, in growing a nitrogen-doped silicon single crystal ingot by the Czochralski method in the present invention, it does not matter whether a magnetic field is applied to the melt or not. The Larsky method also includes a so-called MCZ method for applying a magnetic field.

Further, the epitaxial growth is not limited to the epitaxial growth by the CVD method,
The present invention can also be applied to the case where an epitaxial silicon single crystal substrate is manufactured by performing epitaxial growth by the MBE method.

Further, in the above-described embodiment, even in the case of an antimony-doped silicon single crystal wafer, a wafer having a low crystal defect density on the surface of the wafer and a high gettering effect is obtained, particularly when it is obtained by doping nitrogen. As described above, the present invention is not limited to this, and it is an antimony-doped silicon single crystal wafer, and the density of crystal defects on the surface of the silicon single crystal wafer is as low as 0.1 ke / cm ² or less. Yes, the oxygen precipitates or the oxidation induced stacking fault density after the precipitation heat treatment are 1 × 10
^As many as ⁹ pieces / cm ³ or more are included in the scope of the present invention.

The oxygen precipitates or the oxidation-induced stacking fault density of 1 × 10 ⁹ pieces / cm ³ or more in the present invention means that the heat treatment for epitaxial growth can be performed even after the precipitation heat treatment is applied to the silicon wafer. Also in the case where the precipitation heat treatment is added after the addition, the oxygen precipitates or the oxidation-induced stacking fault density as described above are also included in the scope of the present invention.

[0072]

As described above, in the present invention, by using a silicon wafer doped with nitrogen as a substrate of an epitaxial silicon single crystal wafer, antimony-doped silicon having originally a large number of grown-in defects and a low gettering ability is originally used. Even for single crystal wafers,
A wafer having few grown-in defects and high gettering ability can be obtained. When epitaxial growth is performed on the surface of this wafer, the defect density on the surface of the epitaxial layer and the concentration of heavy metal impurities in the epitaxial layer are low and high quality. The epitaxial silicon single crystal wafer can be produced with high productivity and easily.

[Brief description of drawings]

FIG. 1 is a result chart showing a measurement result of measuring a crystal defect density on a wafer surface before and after epitaxial growth by a particle counter in Examples and Comparative Examples.

FIG. 2 is a result diagram showing measurement results of oxygen precipitate defect densities of wafers by an OPP method after heat treatment for precipitating oxygen precipitates in Examples and Comparative Examples.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-59-75637 (JP, A) JP-A-5-121319 (JP, A) JP-A-6-122592 (JP, A) JP-A-6- 291124 (JP, A) JP 60-251190 (JP, A) JP 62-226897 (JP, A) JP 2-7437 (JP, A) JP 3-164495 (JP, A) JP-A-3-261693 (JP, A) JP-A-5-208892 (JP, A) JP-A-7-1887889 (JP, A) JP-A-9-199381 (JP, A) JP-A-11-135511 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) C30B 1/00-35/00 CA (STN) EUROPAT (QUESTEL)

Claims (13)

(57) [Claims] 1. A antimony-doped silicon single crystal wafer, the density of crystal defects of the antimony-doped silicon single crystal wafer surface Ri der 0.1 Ke / cm ² or less,
Grown with nitrogen doping by the Czochralski method
An antimony-doped silicon single crystal wafer, which is obtained by slicing a silicon single crystal rod . 2. A antimony-doped silicon single crystal wafer state, and are oxygen precipitates or oxidation induced stacking fault density after the precipitation heat treatment of the antimony-doped silicon single crystal wafer is 1 × 10 ⁹ pieces / cm ³ or more, Czochralski
Single crystal ingot grown by nitrogen doping by the method
An antimony-doped silicon single crystal wafer, which is obtained by slicing . 3. An antimony-doped silicon single crystal wafer, wherein the density of crystal defects on the surface of the antimony-doped silicon single crystal wafer is 0.1 unit / cm ² or less,
And oxygen precipitates after the precipitation heat treatment or oxidation induced stacking fault density 1 × 10 ⁹ pieces / cm ³ or more der is, Czochralski
Single crystal ingot grown by nitrogen doping by the method
An antimony-doped silicon single crystal wafer, which is obtained by slicing . 4. An antimony-doped silicon single crystal wafer, wherein the antimony-doped silicon single crystal wafer is obtained by slicing a silicon single crystal rod grown by nitrogen doping by the Czochralski method. An antimony-doped silicon single crystal wafer. 5. The nitrogen concentration of the antimony-doped silicon single crystal wafer is 1 × 10 ^{10 to} 5 × 10 ¹⁵ atoms / cm 3.
The antimony-doped silicon single crystal wafer according to claim 4, which is ³ . 6. The antimony-doped silicon single crystal wafer according to claim 4 or 5, wherein the oxygen concentration of the antimony-doped silicon single crystal wafer is 20 ppma or less. 7. The antimony-doped silicon single crystal wafer has been subjected to a heat treatment at a temperature of 900 ° C. to a melting point of silicon or less, according to any one of claims 4 to 6. The described antimony-doped silicon single crystal wafer. 8. An epitaxial silicon single crystal wafer, wherein an epitaxial layer is formed on the surface layer portion of the antimony-doped silicon single crystal wafer according to any one of claims 1 to 7. An epitaxial silicon single crystal wafer characterized by: 9. A method for producing an antimony-doped silicon single crystal wafer, wherein a silicon single crystal rod doped with antimony and grown with nitrogen is grown by the Czochralski method, and the silicon single crystal rod is sliced to obtain a silicon single crystal. A method for producing an antimony-doped silicon single crystal wafer, which comprises processing into a wafer. 10. When growing a silicon single crystal ingot doped with nitrogen by the Czochralski method, the concentration of nitrogen doped in the single crystal ingot is set to 1 × 10 ^{10 to} 5 × 10 ^15.
The method for producing an antimony-doped silicon single crystal wafer according to claim 9, wherein the atoms / cm ³ is used. 11. The oxygen concentration contained in the single crystal ingot, when growing the nitrogen-doped silicon single crystal ingot by the Czochralski method, is set to 20 ppma or less. The method for producing an antimony-doped silicon single crystal wafer according to claim 10. 12. The antimony-doped silicon single crystal wafer is subjected to heat treatment at a temperature of 900 ° C. to a melting point of silicon or lower.
9. The method for producing an antimony-doped silicon single crystal wafer according to any one of 1. 13. A method for producing an epitaxial silicon single crystal wafer, which comprises producing an antimony-doped silicon single crystal wafer by the method for producing an antimony-doped silicon single crystal wafer according to claim 9. A method for producing an epitaxial silicon single crystal wafer, comprising forming an epitaxial layer on a surface layer portion of the antimony-doped silicon single crystal wafer.